Question: $ { {4} \times \left[\begin{array}{rr}{0} & {-2} \\ {0} & {1}\end{array}\right] = {?} } $
Solution: To multiply a matrix by a number, multiply each item of the matrix by the number. ${\left[\begin{array}{rr}{4}\times{0} & {4}\times{-2} \\ {4}\times{0} & {4}\times{1}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{0} & {-8} \\ {0} & {4}\end{array}\right]}$